import urllib.request
import sys
import http.cookiejar
import urllib.parse
from bs4 import BeautifulSoup
import codecs
import re

#登录页面
url = "http://www.abc.com/login.asp"
#登录Post数据
postdata =urllib.parse.urlencode({ 
"username":"abc",
"password":"abc"
 }).encode('utf-8')
#构造header
header = {
 "Accept":"text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8",
 "Accept-Encoding":"utf-8",
 "Accept-Language":"zh-cn,zh;q=0.8,en-us;q=0.5,en;q=0.3",
 "Connection":"keep-alive",
 "Host":"www.abc.com",
 "Referer":"http://www.abc.com/login.asp",
 "User-Agent":"Mozilla/5.0 (Windows NT 6.1; WOW64; rv:32.0) Gecko/20100101 Firefox/32.0"
 }


req = urllib.request.Request(url,postdata,header)
#获得cookie
cj = http.cookiejar.CookieJar()
opener=urllib.request.build_opener(urllib.request.HTTPCookieProcessor(cj))
r = opener.open(req)

#继续访问登陆后的页面

get_url = 'http://www.abc.com/user/' 
get_request = urllib.request.Request(get_url, headers=header)
get_response = opener.open(get_request)
#打印获得的页面信息
print(get_response.read().decode("utf-8"))
#用bs4可以获得你需要的标签内容
soup = BeautifulSoup(get_response.read(),"html.parser")
jie = soup.find_all('span')
#这里利用正则表达式过滤掉html语言
dr = re.compile(r'<[^>]+>',re.S)
#这里jie[2]表示取符合条件的第三个标签
dd = dr.sub('',str(jie[2]))
print(dd)